How to install NWZ bootloader

nwz_install.txt

All examples below are for NWZ-E580, but the same applies for other targets:
at the root of rockbox resposotory:
> mkdir build_nwze580_bl
> cd build_nwze580_bl
> ../tools/configure
# select NWZ-E580 Series
# Select (B)ootloader
> make
> make -C ../rbutil/mknwzboot
# NOTE: mknwzboot requires to install libcrypto++-dev
> ../rbutils/mknwzboot/mknwzboot -b bootloader-nwze580.sony -o NW_WM_FW.UPG
# mount your player in *mass storage mode* (NOT MTP mode)
> cp NW_WM_FW.UPG /path/to/player/
> umount /path/to/player
> make -C ../utils/nwztools/scsitools/
# assuming your device appears at /dev/sdX
> sudo ../utils/nwztools/scsitools/scsitool /dev/sdX do_fw_upgrade
# the device now reboots, performs the upgrade and leaves the install log at the root of the device